Flexible thin batteries typically comprise contacts for carrying current between the battery electrodes and the device powered by the battery. These contacts are generally in the form of tabs, one or more discrete structures connected at one end to the electrode active material or the electrode substrate and extending from the interior of the battery to the exterior of the battery. Flexible thin batteries further generally comprise a housing or package sealed about the battery perimeter to enclose the electrodes, electrolyte and separator components. The package seal is typically formed by the application of heat or pressure or both to a sealable material to join the opposing surfaces of the package material together.
The tabs present a challenge in this type of construction for several reasons. Where the tab is not integral with the electrode structure, the tabs must be adhered to the electrode structure, usually by welding or adhesively joining the tab to the electrode structure to enable the flow of current. This is a complex process. Further, the tabs must not only contact the electrode structure but must also extend to the exterior of the battery beyond the package or housing to provide a contact with the device that will be powered by the battery. The extension of the tab from the interior to the exterior of the battery packaging can compromise the effectiveness of the package seal in the area where the tab must pass.
Therefore, there is a need for a flexible thin battery where contacts from the electrodes to the battery-powered device are provided without the need for tabs to pass through a seal area of the battery package.